quattro Digest, Vol 10, Issue 86 drive train losses

[Larry C Leung]

Ahh, air friction. And I do recall the "transporter" or "moving brick".
Didn't mention it, because we were comparing wheel horsepower 
(or kW) vs. flywheel power, and wheel power is usually determined 
on the non (vehicle, not wheels!) moving dynomometer.

LL - NY

On Thu, 26 Aug 2004 08:27:30 -0600 tom winter <tom at freeskier.com> writes:
> Yes, frictional losses. As the (dare I admit it) former owner of two 
> '78 VW
> busses I can personally attest for the loss of powder due to 
> friction with
> the air. Particularly headwinds!
> 
> Of course if I had done a turbo quatto conversion to either of them 
> it might
> not have been such an issue.
> 
> Tom
> 
> 
> on 8/26/04 8:08 AM, Larry C Leung at l.leung at juno.com wrote:
> 
> > Mike,
> > 
> > The energy goes into various places besides making the car go
> > forwards (or backwards!), mostly due to what is generally called
> > frictional losses. Potential energy sinks:
> > 
> > Heat (into the drivetrain parts, air, lubes in the driveline, etc. 
> -
> > largest of the losses)
> > Sound (all that whirring noise, that's losses!)
> > Vibration (essentially work that's wasted in making parts vibrate 
> up and
> > down or whatever)
> > Hysterisis (flexural absorbtion in the tires)
> > Other mechanical losses (now we're getting into minor bits, shock
> > absorber heat, spring flex, etc)
> > 
> > Since there are more bits to absorb in an AWD car vs. 2WD, there 
> tends to
> > be greater losses.
> > Don't know what losses are caused by the diffy fluids that shall 
> remain
> > nameless in the center of post
> > '89 quattros......, although my understanding of those particular 
> diffs
> > (also known as Quaiffe's) is it's
> > mostly a mechanical set-up, with lot's of little bits, allowing 
> for much
> > of the same losses as the overall,
> > just on a much smaller scale....
> > 
> > LL - NY - a.k.a. the Physics Teacher
> > 
> > 
> >> ------------------------------
> >> 
> >> Date: Thu, 26 Aug 2004 08:27:17 -0400
> >> From: Mike Arman <armanmik at earthlink.net>
> >> Subject: drive train losses
> >> To: quattro at audifans.com
> >> Message-ID: 
> <4.2.0.58.20040826073546.00ad7bb8 at mail.earthlink.net>
> >> Content-Type: text/plain; charset="us-ascii"
> >> 
> >> 
> >> 
> >> I have to take issue with the idea that you can "lose" 100 hp in 
> the
> >> drive 
> >> train.
> >> 
> >> Where does this energy go? 100 hp is (at 33,000 ft. lbs per hp) 
> over
> >> 3 
> >> million foot pounds, at 746 watts per hp, it is 74.6 KW, enough 
> to
> >> run your 
> >> whole house, central A/C, big screen TV and all. This energy 
> simply
> >> does 
> >> NOT "disappear" in the drive train.
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> > 
> 
> 
>